Water is essential for life on Earth, yet little is known about how water acts as a trophic currency, a unit of value in determining species interactions in terrestrial food webs. We tested the relative importance of groundwater and surface water in riparian food webs by manipulating their availability in dryland floodplains. Primary consumers (crickets) increased in abundance in response to added surface water and groundwater (contained in moist leaves), and predators (spiders and lizards) increased in abundance in response to added surface water, in spite of the presence of a river, an abundant water source. Moreover, the relative magnitude of organism responses to added water was greatest at the most arid site and lowest at the least arid site, mirroring cricket recruitment, which was greatest at the least arid site and lowest at the most arid site. These results suggest that water may be a key currency in terrestrial dryland food webs, which has important implications for predicting ecosystem responses to human‐ and climate‐related changes in hydrology and precipitation.

Oil and gas extraction in the western United States generates significant volumes of produced water (PW) that is typically injected into deep disposal wells. Recently, crop irrigation has emerged as an attractive PW reuse option, but the impact on plant immune response is not known. In this study, we conducted a 3-month greenhouse pot study. Spring wheat (Triticum aestivum) was irrigated 3 times a week with 150 mL (∼80–100% of soil water holding capacity) with one of four irrigation treatments: tap water control, 10% PW dilution, 50% PW dilution, and salt water (NaCl50) control containing the same amount of total dissolved solids as PW50 to determine the effect on disease resistance. The wheat leaves were inoculated with either bacterial or fungal pathogens and changes in pathogenesis-related PR-1 and PR-5 gene expression were measured from the leaf tissue. PW50 experienced the largest relative suppression of PR-1 and PR-5 gene expression compared to noninfected wheat, followed by PW10, NaCl50, and the tap water control. A combination of PW contaminants (boron, total petroleum hydrocarbons, and NaCl) are likely reducing PR-gene expression by reallocating metabolic resources to fight abiotic stresses, which then makes it more challenging for the plants to produce PR genes to fight pathogens. This study provides the first evidence that plant disease resistance is reduced due to irrigation with reused PW, which could have negative implications for food security.

Asia accounts for 70% of the world's irrigated area and is home to some of the oldest and largest irrigation schemes. While these irrigation schemes played an important role in ensuring food security for billions of people in the past, their current state of affairs leaves much to be desired. This paper takes forward the IWMI-FAO-ADB (Asian Development Bank) recommendation of a five pronged approach for revitalizing Asia's irrigation and provides a region specific road map for doing this. The underlying principle of these multiple strategies is the belief that the public institutions at the heart of irrigation management in Asia need to give up comfortable rigidity and engage with individual users' needs and the demands placed by larger societal chang | Aditi Mukherji et al., 'Growing more food with less water: how can revitalizing Asia's irrigation help?', 2014

Aditi Mukherji, T. Facon, S David, Colin J. Chartres, 'Growing more food with less water: how can revitalizing Asia?s irrigation help?', 2014 | Irrigation has always played a central role in the agrarian economy of Asia, from supporting famed hydraulic civilizations in the ancient past to spearheading Green Revolution in the 1960s and 1970s,. Asia accounts for 70% of the world?s irrigated area and is home to some of the oldest and largest irrigation schemes. While these irrigation schemes played an important role in ensuring food security for billions of people in the past, their current state of affairs leaves much to be desired. The purpose of this paper is analyze the current trends in irrigation in Asia and suggest ways and means for revitalizing irrigation for meeting our future food needs and fuelling agricultural growth. The paper recommends a five pronged approach for revitalizing Asia?s irrigation and provides region specific strategies for the same. The underlying principal of these multiple strategies is the belief that the public institutions at the heart of irrigation management in Asia need to give up comfortable rigidity and engage with individual users? needs and the demands placed by larger societal changes

Plant water stress can affect selectivity by insect herbivores. Numerous studies have shown greater insect preference for water-stressed plants, but others have reported the opposite response. We evaluated leaf consumption by adults of Nyctelia circumundata (a chewing insect) in leaves of Larrea divaricata and Prosopis alpataco. Three bioassays (two-way choice tests) were performed: two intra-specific comparisons between well-watered (+W) and water-stressed (−W) leaves of each species and one inter-specific comparison between leaves of the two species. Leaf biomass was reduced by water stress in both species. Nitrogen concentration in leaves (N) was reduced by drought in P. alpataco. In contrast, total phenolics and specific leaf area (SLA) did not differ between treatments within species. Nyctelia circumundata did not show preference by any water supply regimes in intra-specific comparisons. In contrast, in inter-specific choice tests, it showed a marked preference for P. alpataco, which is the species with the highest nitrogen concentration and lowest total phenolics concentration. In intra-specific comparisons, maximum leaf consumption was inversely related to SLA in both species. Furthermore, in P. alpataco, N concentration was positively related to maximum leaf consumption and negatively related to leaf water content (LWC). In contrast, in inter-specific comparisons, total phenolics was negatively related to maximum leaf consumption, while N concentration exhibited the opposite trend. These results suggest that food selection is a hierarchical process where chemical attributes (i.e., total phenolics and N) are taken into account for species selection, and physical attributes (i.e., SLA and LWC) for choosing individuals inside species.

Mentha spicata L. disappears in winter. The lack of fresh mint during the cold season can be a limiting factor for the preparation of mint tea. A fresh taste source that can be kept during winter is mint essential oil. As the oil is not soluble in water, a food-approved, water-soluble essential oil microemulsion was studied, investigating different surfactants, in particular Tween® 60. The challenge was to dissolve an extremely hydrophobic essential oil in a homogeneous, stable, transparent, and spontaneously forming solution of exclusively edible additives without adulterating the original fresh taste of the mint. Making use of the microemulsions’ water and oil pseudo-phases, hydrophilic sweeteners and hydrophobic dyes could be incorporated to imitate mint leaf infusions aromatically and visually. The resulting formulation was a concentrate, consisting of ∼ 90% green components, which could be diluted with water or tea to obtain a beverage with a pleasant minty taste.

A green, switchable water dispersive liquid–liquid microextraction (SWDLL-ME) method is introduced for the first time as a preconcentration/separation tool for measuring trace levels of cadmium (Cd) in real water and food samples. In the present study, a switchable aqueous solution of polar organic solvent (acetonitrile) was reversibly switched (on and off) from miscible monophasic to immiscible biphasic in aqueous medium by exposure to an anti-solvent trigger (CO₂). The developed SWDLL-ME was successfully applied as an extraction method for the extraction of a Cd–PAN complex (1-(2-pyridylazo)-2-naphthol) in polar organic solvent (PS). The solvent enriched phase containing Cd–PAN was separated from the switchable water (SW) and treated with 200 μL of 0.1 mol L⁻¹ HNO₃ with ethanol (1 : 1, v/v) in order to reduce its viscosity, and it was then easily injected into a GFAAS for analysis. The SW was reused for the next assay after the removal of CO₂. The switching phenomenon of the SW from low to high polarity was confirmed by FTIR spectroscopy and conductivity measurements. The enrichment factor and limit of detection of the proposed method were 22 and 0.38 ng L⁻¹, respectively. Validation of the developed method was carried out by analyzing certified reference materials (SLRS-4 Riverine water and NIST SRM 1515 Apple leaves).

Multifunctional crops can simultaneously contribute to multiple societal objectives. As a result, they represent an attractive means for improving rural livelihoods. Moringa oleifera is an example of a multifunctional crop that produces nutritious leaves with uses as food, fodder, and a biostimulant to enhance crop growth. It yields seeds containing a water purifying coagulant and oil with cosmetic uses and possible biofuel feedstock. Despite Moringa oleifera's (and other multifunctional crops') various Food-Energy-Water uses, optimizing the benefits of its multiple uses and livelihood improvements remains challenging. There is a need for holistic approaches capable of assessing the multifunctionality of agriculture and livelihood impacts. Therefore, this paper critically evaluates Moringa oleifera's Food-Energy-Water-Livelihood nexus applications to gain insight into the tradeoffs and synergies among its various applications using a systems thinking approach. A systems approach is proposed as a holistic thinking framework that can help navigate the complexity of a crop's multifunctionality. The “Success to the Successful” systems archetype was adopted to capture the competition between the need for leaf yields and seed yields. In areas where there is energy and water insecurity, Moringa oleifera seed production is recommended for its potential to coproduce oil, the water purifying coagulant, and a residue that can be applied as a fertilizer. In areas where food insecurity is an issue, focusing on leaf production would be beneficial due to its significance in augmenting food for human consumption, animal feed, and its use as a biostimulant to increase crop yields. A causal loop diagram was found to effectively map the interconnections among the various uses of Moringa oleifera and associated livelihood improvements. This framework provides stakeholders with a conceptual decision-making tool that can help maximize positive livelihood outcomes. This approach can also be applied for improved management of other multifunctional crops.